Reaction of dimethyl trisulfide with hemoglobin

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Abstract

When samples of blood were spiked with the novel cyanide antidote dimethyl trisulfide (DMTS), the color of the blood was observed to darken. Additionally, recoveries of DMTS from spiked blood were low, and the loss of DMTS was more pronounced in 5-day old blood samples than in equivalently spiked 4-month old blood samples. It was hypothesized that DMTS oxidizes hemoglobin (Hb) in the red blood cells to yield methemoglobin (metHb), methanethiol (MeSH), methyl hydrogen disulfide (MeSSH), and hydrogen sulfide (H2S). The aim of this research was to determine the reactants, products, and chemical kinetics of the reactions of DMTS with Hb isolated from red blood cells, and with Hb in blood. The changes induced in the Hb absorption spectrum by the addition of DMTS were found to closely match those induced by the known metHb former sodium nitrite. These spectral shifts indicating the conversion of Hb to metHb were observed systematically when DMTS was added to red blood cell or Hb solutions. The formation of metHb was monitored as a function of time following the addition of a known amount of DMTS. The rate of the reaction of DMTS with Hb increased in the presence of the reducing agent dithionite (DT). H2S, MeSH, and MeSSH were expected as reaction products, but were not directly observed in headspace samples. 2,4-dithiapentane had not been predicted as a reaction product, but was observed in the headspace above reaction mixtures of DMTS and Hb. The 2,4-dithiapentane is hypothesized to be a reaction product of MeSH with formaldehyde-based polymers in the vial cap.